The present invention relates generally to push back pallet storage systems.
More particularly, the invention refers to an improvement in depth pallet storage systems referred to as push back that allow a fast operation speed and high storage density. In these storage systems, pallets are stored placed on a slightly inclined plane so that the last one was introduced is the first one that is extracted. Several levels may be arranged in height with which a simple selectivity of the stock is obtained in contrast with block stacking conventional procedures.
In conventional push back systems, a forklift truck places the pallet loads in the system on a platform that may be moved lengthwise so that each platform is pushed back by the next loaded pallet. For unloading, each platform slips forward in the rack as the previous pallet is extracted with the help of the slightly inclined plane on which the platforms are arranged. Loading and unloading of the pallets is carried out through a central passageway wherein the forklift truck moves.
The movable platforms in the conventional push back system basically comprise a metallic frame provided with wheels or rollers. One of these structures is described in the U.S. Pat. No. 5,312,004 which refers to a slidable platform for a push back system. The platform comprises two rails acting as a guide for rollers fitted in frames running above the rails.
Although this structure is effective, it suffers from several disadvantages such as a great constructive complexity causing, among other things, that the necessary inclination for unloading the pallets by gravity must be high.